Production of nitrogen-free alkali metal carbonates



Patented Sept. 17, 1935 UNITED STATES PATENT OFFICE PRODUCTION OF NITROGEN-FREE ALKALI METAL CARBONATES Robert B. MacMullin and George Lewis Cunningham, Niagara Falls, N. Y., assignors to The Mathieson Alkali Works, Inc., New York, N. Y., a corporation of Virginia No Drawing. Application April 21, 1932, Serial No. 606,760

2 Claims.

and the production of this compound is described in an application filed by Robert B. MacMullin on March 21, 1932, and issued as Patent No. 1,980,691 on Nov. 13, 1934.

We have discovered that sodium ammonium carbonate dihydrate can be converted to nitrogenfree sodium carbonates by heating to temperatures upwards of about 50 C. to drive off ammonia, carbon dioxide and water. While water is driven off during the conversion, its presence, as water of hydration of the sodium ammonium carbonate, appears to be important in the requisite elimination particularly of nitrogen as ammonia. The sodium carbonates so produced are substantially free from nitrogen compounds such as cyanates, cyani-des, carbamates, ammonia and ammonium carbonates. By controlling the temperature of heating, various sodium carbonates can be produced.

In the production of anhydrous sodium carbonate, Na2CO3, the sodium ammonium carbonate dihydrate is heated to a temperature upwards of about 104 C. The reaction may be illustrated as follows:

The reaction is substantially complete at temperatures approximating 150 C.

In the production of sodium carbonate monohydrate, NazCOs-HzO, the sodium ammonium carbonate dihydrate is heated to a temperature approximating 50-104 C. The reaction may be illustrated as follows:

In the production of sodium sesquicarbonate dihydrate,

NaI-ICO3-NazCO3-2H20,

the sodium ammonium carbonate dihydrate is 15 heated to a temperature approximating 50 C. The reaction may be illustrated as follows:

We claim:

1. In the production of sodium carbonate monohydrate from sodium ammonium carbonate dihydrate, the improvement which comprises heating the latter compound to a temperature ap- 25 proximating 50-104 C.

2. In the production of sodium sesquicarbonate dihydrate from sodium ammonium carbonate dihydrate, the improvement which comprises heating the latter compound to a temperature ap- 3O proximating 50 C.

ROBERT B. MACMULIJN. GEORGE LEWIS CUNNINGHAM. 

